2I4 PRACTICAL ORGANIC CIIKMISTKV
on cooling, and is pure cliphenylmcthane ; m. p. 25—26°.
Yield, 14 grams.
QH.CHXl + CflHfl = C(IHflCH2CnMri + HC1.
Properties.—-Colourless needles; m. p. 26.......27 ' ; I), p. 262'.
On boiling with potassium clichromate and sulphuric acid it is
oxidised to benzophenone, C0H.-CrLC(!Hr, -h Go =•• C0H.-.CO.Ct;H5
+ HoO. See AppendL\\ p. 312.
Friedel, Crafts, Compt rend., 1877, 145° ; E- '™d O. Fischer,
Annalcn, 1878, 197, 252 ; Biltz, Ber., 1893, 26, 1961.
200 grms. (230 c.c.) benzene.
40 „ (26 c.c,) chloroform.
30 „ aluminium chloride.
The benzene and chloroform are mixed together and
dehydrated over calcium chloride overnight before use. The
liquid is then decanted into a retort connected with an upright
condenser,* and the powdered aluminium chloride added in
portions of about 5 grams at a time at intervals of five minutes
and well shaken. On the addition of the chloride the reaction,
sets in spontaneously, and the liquid begins to boil with evolu-
tion of hydrochloric acid. The aluminium chloride gradually
dissolves, forming a dark-brown liquid. The reaction is com-
pleted by boiling for half an hour on the sand-bath. When.
cold, the contents of the retort arc poured into an equal volume
of cold water, which decomposes the aluminium compound with
evolution of heat, and the free hydrocarbon dissolves in the
excess of benzene with a reddish-brown colour. The upper layer
of benzene is separated from the aqueous portion, and the former
dehydrated over calcium chloride. The excess of benzene is
distilled off on the water-bath, and the dark-coloured residue
fractionated up to 200°. It is then distilled /// tnicito from a
retort without condenser. At first an oil distils, which consists
of impure diphenylmethane. When most of the cliphenyl
compound has passed over, the distillation suddenly slackens.
The receiver is now changed, and the retort more strongly